The LG G4 was released in the US in early June 2015, as always focusing on high-end specifications and a refined fashion sense that makes it stand out in the premium smartphone market. Each version of the phone will have a different model number based on if it is sold by a carrier or sold by LG as a US Unlocked or International model.

The 2 pins to the left side of the camera are for a Qi Wireless charging, which you can upgrade your backplate with, which has a sticker in it that normally only carries a NFC sticker without Qi. Qi+NFC stickers can be found all over amazon for around 10$.

Now to the 4 pins to the right of the battery.

The lower 2 of them are NFC as you can already see on your backplate that came with your LG G4.

I dont know what the upper 2 are for, but i dont think their for a "Radio sticker" as i havent seen any and the G4 uses, same as on some Apple devices, the headphones as an antenna.